cargo handling vehicle

Abstract

A cargo handling vehicle is provided that can avoid contact with an obstacle above and suppress a decrease in work efficiency. [Solution] A loading vehicle 1 comprising a vehicle body 2, a loading device 3, a control unit 4, and a sensor unit 5 that detects objects above the vehicle body 2, wherein the sensor unit 5 sets a first area in front of the vehicle body 2 during lifting and lowering operations to detect the upper end of the loading device 3, and when the upper end is detected in the first area, sets a second area directly above the vehicle body 2 during traveling operations, and sets a third area behind the vehicle body 2 to detect obstacles C above the work area, and the control unit 4 stops the vehicle body 2 from traveling or restricts its speed when an upper obstacle C is detected in the second or third area.

Description

[Technical Field]

[0001] The present invention relates to a cargo handling vehicle such as a forklift. [Background technology]

[0002] A known example of a conventional cargo handling vehicle is described in Patent Document 1. The cargo handling vehicle described in Patent Document 1 detects obstacles in the traveling direction. Specifically, the cargo handling vehicle described in Patent Document 1 uses the detection results of the obstacle sensor to calculate the height H2 of the mast based on the height of the obstacle sensor, calculates a first line connecting the obstacle sensor to a position that is a first distance Lf away from the obstacle sensor in the traveling direction, calculates a second line connecting the obstacle sensor to a position that is a height H2 away from the above position in the height direction, and calculates the angle θf between the first line and the second line. The cargo handling vehicle described in Patent Document 1 prohibits or stops traveling when an obstacle is detected by the obstacle sensor within the range of angle θf.

[0003] The cargo handling vehicle described in Patent Document 1 also detects obstacles above. Specifically, the cargo handling vehicle described in Patent Document 1 uses the detection results of the obstacle sensor to calculate a first height H4 that is lower than the height to an obstacle above the cargo handling vehicle based on the height of the obstacle sensor, and calculates a second height H6 to the top end of the mast based on the height of the obstacle sensor. The cargo handling vehicle described in Patent Document 1 prohibits or stops raising the mast when the second height H6 becomes equal to or greater than the first height H4.

[0004] The cargo handling vehicle described in Patent Document 1 can avoid contact with obstacles above. However, the cargo handling vehicle described in Patent Document 1 prohibits or stops travel when it detects an obstacle a certain distance ahead in its direction of travel, so it also prohibits or stops travel when it approaches a wall or shelf within the work area. As a result, the cargo handling vehicle described in Patent Document 1 frequently prohibits or stops travel in narrow cargo handling work sites, significantly reducing work efficiency. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-111138 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cargo handling vehicle that can avoid contact with an overhead obstacle and suppress a decrease in work efficiency. [Means for solving the problem]

[0007] In order to solve the above problem, the cargo handling vehicle according to the present invention comprises: a vehicle body that travels in a predetermined working area; a cargo handling device provided at the front side of the vehicle body and performing a lifting operation; a control unit that controls the traveling operation and the lifting operation; a sensor unit that detects objects in a first area, a second area, and a third area above the vehicle body; A cargo handling vehicle comprising: The sensor unit During the lifting / lowering operation, the first area is set in front of the vehicle body to detect the upper end of the cargo handling device, When the upper end portion is detected in the first area, during the traveling operation, the second area is set directly above the vehicle body, and the third area is set behind the vehicle body to detect an obstacle above the working area; The control unit When the above obstacle is detected in the second area or the third area, the vehicle body is stopped or its speed is restricted.

[0008] In the cargo handling vehicle, The sensor unit The rear end position of the second area is set to the same position as or forward of the rear end position of the vehicle body, The upper end position of the second area can be configured to be set at the same position as or above the upper end position of the first area.

[0009] In the cargo handling vehicle, The sensor unit The upper end position of the third area is set higher than the upper end position of the second area, The front end position of the third area may be set forward of the rear end position of the second area.

[0010] In the cargo handling vehicle, The control unit outputs a cargo handling operation signal to the sensor unit during the lifting operation, The sensor unit The second area and the third area can be configured to be set when the cargo handling operation signal is not input and when the upper end portion is detected in the first area.

[0011] In the cargo handling vehicle, the control unit outputs a reverse signal to the sensor unit when the vehicle body is moving backward; The sensor unit The second area and the third area may be set when the reverse signal is input and the upper end is detected in the first area.

[0012] In the cargo handling vehicle, The sensor unit outputting a first detection signal when detecting the cargo handling device in the first area; outputting a second detection signal when the upper obstacle is detected in the second area; outputting a third detection signal when the upper obstacle is detected in the third area; The sensor may be configured to include a signal line for inputting the output first detection signal to itself.

[0013] In the cargo handling vehicle, The control unit may be configured to limit the speed of the vehicle body when the upper end portion is detected in the first area during the traveling operation. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a cargo handling vehicle that can avoid contact with an obstacle above and suppress a decrease in work efficiency. [Brief explanation of the drawings]

[0015] [Figure 1] 1A and 1B are a side view and a plan view, respectively, of a forklift according to a first embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram of a sensor unit and a control unit according to the first embodiment. [Figure 3] FIG. 10 is a diagram showing a detection area during lifting and lowering operations. [Figure 4] FIG. 10 is a diagram showing a detection area when the lifting operation is stopped and the vehicle is stopped. [Figure 5] FIG. 10 is a diagram showing a detection area during traveling (reverse traveling). [Figure 6] 10A and 10B are a side view and a plan view, respectively, of a forklift according to a second embodiment of the present invention; [Figure 7] FIG. 10 is a block diagram of a sensor unit and a control unit according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a cargo handling vehicle according to the present invention will be described with reference to the accompanying drawings.

[0017] [First embodiment] Fig. 1 shows a forklift 1 according to a first embodiment of the present invention. The forklift 1 according to the first embodiment is a counterbalance type forklift and corresponds to the "cargo handling vehicle" of the present invention. The forklift 1 travels and handles cargo in a predetermined work area.

[0018] The work area is an area within any building such as a factory or warehouse. Above the work area, there is an obstacle C (hereinafter referred to as "upper obstacle C") such as a low ceiling, a gate, or a protrusion. In addition, the work area is provided with a plurality of shelves (not shown), on which cargo W and the like are stored.

[0019] The forklift 1 includes a vehicle body 2, a cargo handling device 3, a control unit 4, and a sensor unit 5.

[0020] The vehicle body 2 has front and rear wheels at the bottom, and a driver's seat and head guard at the top. The front wheels are drive wheels driven by a traction motor, and the rear wheels are steered wheels steered (turned) by a steering motor. The driver's seat is the operator's seat, and the head guard is a protective frame that protects the operator in the driver's seat from falling objects.

[0021] The vehicle body 2 is equipped with an accelerator and a brake at the feet of the driver's seat. The accelerator is an accelerator pedal configured to be operable by an operator in the driver's seat by stepping on it with his foot. When the accelerator is in the on state (pedal depressed), it accelerates the vehicle body 2 in accordance with the amount of pedal depression (accelerator opening), but when it switches from the on state to the off state (pedal not depressed), it generates weak regenerative braking to decelerate the vehicle body 2. The brake is a brake pedal configured to be operable by an operator in the driver's seat by stepping on it with his foot. When the brake is in the on state (pedal depressed), it generates regenerative braking stronger than the accelerator regenerative braking to decelerate the vehicle body 2, but when it is in the off state, it does not generate regenerative braking. The operator can cause the vehicle body 2 to perform driving operations such as acceleration and deceleration by operating the accelerator and / or brake.

[0022] The vehicle body 2 is equipped with a steering wheel, a forward / reverse lever, and a load handling lever (tilt lever and lift lever) in front of the driver's seat. The steering wheel is connected to the rear wheels via a steering control mechanism 4C, which will be described later. By turning the steering wheel, the operator can change the direction (turning angle) of the rear wheels depending on the direction of rotation. The forward / reverse lever is provided below the steering wheel and switches the traveling operation of the vehicle body 2 between forward and reverse. The operator can move the vehicle body 2 forward by tilting the forward / reverse lever forward (forward position) and turning on the accelerator, and can move the vehicle body 2 backward by tilting the forward / reverse lever backward (reverse position). The load handling lever is connected to the load handling device 3 via a load handling control mechanism 4B, which will be described later. The operator can cause the load handling device 3 to perform a load handling operation by operating the load handling lever.

[0023] The cargo handling device 3 includes a mast, a backrest and forks, a tilt cylinder, and a lift cylinder, and performs cargo handling operations, including raising and lowering operations of the mast and forks.

[0024] The mast is provided at the front of the vehicle body 2 and raises and lowers the forks. The mast comprises an outer mast and an inner mast. The outer mast comprises a pair of left and right guide rails that extend vertically, and a cross beam that connects the upper ends of the guide rails. The inner mast comprises a pair of left and right rails that extend vertically, and a cross beam (connecting member) that connects the upper ends of the rails. The inner mast is provided inside the guide rails of the outer mast, and rises and lowers along the guide rails of the outer mast. The outer mast does not rise and lower.

[0025] The backrest is a frame that prevents the load W loaded on the forks from tipping backward, and has a lift bracket attached to its bottom. The lift bracket supports the forks and moves up and down along the mast. In other words, when the mast (inner mast) moves up and down, the backrest (including the lift bracket) and forks move up and down. The forks are a pair of L-shaped arms attached to the front of the backrest.

[0026] The tilt cylinder is a hydraulic cylinder that tilts the mast forward and backward. For example, when the tilt lever is tilted forward, the tilt cylinder extends and the mast tilts forward, and when the tilt lever is tilted backward, the tilt cylinder contracts and the mast tilts backward. When the tilt lever is returned to the neutral position (a position where the mast does not tilt forward or backward), the mast stops tilting.

[0027] The lift cylinder is a hydraulic cylinder used to raise and lower the mast. For example, when the lift lever is tilted forward, the lift cylinder contracts and the inner mast lowers, and when the lift lever is tilted backward, the lift cylinder extends and the inner mast rises. When the lift lever is returned to the neutral position (a position where the inner mast is neither tilted forward nor backward), the raising and lowering of the inner mast stops.

[0028] The control unit 4 controls the traveling operation of the vehicle body 2 and the loading operation of the loading device 3. As shown in Fig. 2, the control unit 4 includes a vehicle control unit 4A, a loading control mechanism 4B, a steering control mechanism 4C, and a traveling control mechanism 4D.

[0029] The vehicle control unit 4A controls the traveling and loading operations by controlling the load handling control mechanism 4B, the steering control mechanism 4C, and the traveling control mechanism 4D. The vehicle control unit 4A acquires detection signals required for controlling the traveling and / or loading operations from various sensors (excluding the sensor unit 5). Furthermore, the vehicle control unit 4A transmits and receives signals to and from the sensor unit 5. The vehicle control unit 4A is composed of, for example, an MPU, a memory, etc.

[0030] The cargo handling control mechanism 4B includes, for example, a cargo handling inverter, a cargo handling motor, a hydraulic circuit, etc. The vehicle control unit 4A acquires detection signals relating to the amount of operation of the cargo handling levers (tilt lever and lift lever) and controls the cargo handling device 3 via the cargo handling control mechanism 4B.

[0031] The steering control mechanism 4C includes, for example, a steering motor, a power steering device, a hydraulic circuit, etc. The vehicle control unit 4A acquires detection signals relating to the direction and amount of rotation of the steering wheel, and controls the rear wheels, which are steered wheels, via the steering control mechanism 4C.

[0032] The cruise control mechanism 4D includes, for example, a cruise inverter, a cruise motor, and a hydraulic circuit. The vehicle control unit 4A acquires detection signals related to the accelerator opening, brake state, vehicle speed, etc., and controls the front wheels, which are the drive wheels, via the cruise control mechanism 4D. As part of this control, the vehicle control unit 4A performs speed control to bring the traveling speed of the vehicle body 2 closer to a predetermined target speed. Specifically, the vehicle control unit 4A acquires the traveling speed of the vehicle body 2 based on the detection signal of a vehicle speed sensor, and calculates the target speed based on the detection signal of an accelerator sensor and / or a brake sensor. The vehicle control unit 4A performs PI control or PID control to bring the traveling speed closer to the target speed. The target speed is calculated, for example, using the formula: target speed = set speed × accelerator opening [%]. The set speed is a speed preset in the vehicle control unit 4A.

[0033] The sensor unit 5 is an area sensor that detects objects in a predetermined detection area. In this embodiment, a single 2D-LiDAR is used as the sensor unit 5. As shown in FIG. 1, the sensor unit 5 (2D-LiDAR) is attached to the upper part of the vehicle body 2 at an angle that allows it to irradiate laser light vertically upward with respect to the road surface. Specifically, the sensor unit 5 is attached to the upper part of the head guard at a central position in the left-right direction. The detectable area R of the sensor unit 5 is limited to the left-right center of the forklift 1, and is 180° or more in the front-rear direction (180° in FIG. 1). Note that when a 3D-LiDAR is used as the sensor unit 5, the detectable area R can have a width in the left-right direction depending on the irradiation range of the laser light.

[0034] LiDAR can be classified into a data output type and an area setting type. A data output type LiDAR outputs distance information acquired from reflected laser light for each irradiation angle of the laser light. On the other hand, an area setting type LiDAR outputs a detection signal when an object is detected in a set area. The sensor unit 5 of this embodiment is an area setting type 2D-LiDAR. Furthermore, as an area setting type 2D-LiDAR, for example, an area setting type range sensor manufactured by Hokuyo Automotive Co., Ltd. can be used.

[0035] As shown in FIG. 2, the sensor section 5 includes a sensor main circuit section 5A, a sensor control section 5B, a plurality of (five in this embodiment) input ports P1 to P5, and a plurality of (three in this embodiment) output ports P6 to P8.

[0036] The sensor main circuit 5A includes a light-projecting unit that projects laser light and a light-receiving unit that receives reflected laser light. The sensor control unit 5B includes a setting processing unit that sets a detection area in the detectable area R, and a drive processing unit that drives the light-projecting unit and the light-receiving unit to detect an object in the detection area.

[0037] The setting processing unit can simultaneously set multiple detection areas (up to three in this embodiment) in the detectable area R. The setting processing unit stores up to three detection area patterns in advance, associated with the input signals input to the input ports P1 to P5. Details of the detection area patterns will be described later.

[0038] The drive processing unit outputs a first detection signal from output port P6 when an object is detected in a first detection area R1 (described later) of the three detection areas, outputs a second detection signal from output port P7 when an object is detected in a second detection area R2 (described later), and outputs a third detection signal from output port P8 when an object is detected in a third detection area R3 (described later). The first to third detection signals are on signals (high-level signals) or off signals (low-level signals). In the case of an off signal, for example, it becomes high level when no object is detected and becomes low level when an object is detected. Note that a method for detecting an object using laser light can be used, using known technology (for example, a TOF method, etc.), so a description thereof will be omitted.

[0039] In this embodiment, the input port P2 and the output port P6 are connected by a signal line L1. The first detection signal output from the output port P6 is input to the input port P2. This reduces the number of signal lines connecting the control unit 4 (vehicle control unit 4A) and the sensor unit 5, and reduces the number of signals output from the control unit 4 (vehicle control unit 4A) to the sensor unit 5.

[0040] The vehicle control unit 4A outputs a cargo handling operation signal to the sensor unit 5 when the cargo handling device 3 is raised or lowered, and outputs a reverse signal when the vehicle body 2 is reversed. The cargo handling operation signal is input to input port P4, and the reverse signal is input to input port P5. The cargo handling operation signal is, for example, a signal that goes high when the lift lever is in a forward tilt position or a backward tilt position, and goes low when the lift lever is in a neutral position. The reverse signal is, for example, a signal that goes high when the vehicle body 2 is reversed, and goes low when the vehicle body 2 is moving forward or is stopped.

[0041] The detection area patterns for the input signals input to input ports P1 to P5 are as shown in Table 1. In Table 1, the presence of an input signal is indicated by a circle, and the absence of an input signal is left blank. Furthermore, input ports P1 and P3 are unused, and for input patterns other than patterns (1) to (8) in Table 1, no detection area is set.

[0042] [Table 1]

[0043] In patterns (1), (2), and (7), the sensor unit 5 sets a detection area to determine the position of the upper end of the cargo handling apparatus 3 (hereinafter referred to as the upper end position). In patterns (3) and (5), the sensor unit 5 does not set a detection area. In pattern (4), the sensor unit 5 is in a so-called self-holding state. In pattern (6), the sensor unit 5 sets a detection area to determine the presence or absence of an upper obstacle C with which there is a possibility of a collision. In pattern (8), the sensor unit 5 sets a detection area to determine the upper end position of the cargo handling apparatus 3, and also sets a detection area to determine the presence or absence of an upper obstacle C. Here, the upper end position of the cargo handling apparatus 3 means the highest position among the position of the upper end of the mast, the position of the upper end of the backrest, and the position of the upper end of the load W held by the forks. In the following, the cargo handling apparatus 3 is assumed to include the load W held by the cargo handling apparatus 3.

[0044] In pattern (1), a cargo handling operation signal is input to input port P4. In this case, the sensor unit 5 sets a first detection area R1 as the detection area, as shown in Fig. 3(A). Pattern (1) occurs when a cargo handling operation is performed to raise or lower the cargo handling device 3, and the upper end position of the cargo handling device 3 (the position of the upper end of the mast) is below the first detection area R1.

[0045] The first detection area R1 includes a first area r1 in front of the vehicle body 2 and above the cargo handling apparatus 3 (strictly speaking, the cargo handling apparatus 3 with its internal mast not raised). The upper end of the first area r1 is the upper end of the first detection area R1, and the front end of the first area r1 is the front end of the first detection area R1. The first area r1 corresponds to the height of an upper obstacle C. For example, the height of an upper obstacle C that may come into contact with the cargo handling apparatus 3 holding multiple loads W or the cargo handling apparatus 3 with its internal mast raised is measured in advance, and the area where the upper obstacle C exists is set as the first area r1. In this embodiment, the first area r1 is set to be rectangular, but its shape can be changed as appropriate.

[0046] In pattern (2), a first detection signal is input to input port P2, and a cargo handling operation signal is input to input port P4. In this case, the sensor unit 5 sets a first detection area R1 as the detection area, as shown in FIG. 3(B). The range of the detection area is the same as in FIG. 3(A). Pattern (2) is a case where a cargo handling operation is performed related to the lifting and lowering operation of the cargo handling device 3, and the upper end position of the cargo handling device 3 (the position of the upper end of the cargo W) is located in the first detection area R1.

[0047] In pattern (3), no input signal is input to input ports P2, P4, and P5. In this case, the sensor unit 5 does not set a detection area, as shown in FIG. 4(A). Pattern (3) is a case where the loading / unloading device 3 is not moving up or down, the vehicle body 2 is stopped (or moving forward), and the upper end position of the loading / unloading device 3 (the position of the upper end of the mast) is below the first detection area R1. Note that the sensor unit 5 does not need to store pattern (3), in which no detection area is set.

[0048] In pattern (4), a first detection signal is input to input port P2. In this case, the sensor unit 5 sets a first detection area R1 as the detection area, as shown in FIG. 4(B). The range of the detection area is the same as in FIGS. 3(A) and (B). Pattern (4) is a case where the loading / unloading device 3 is not moving up or down, the vehicle body 2 is stopped (or moving forward), and the upper end position of the loading / unloading device 3 (the position of the upper end of the cargo W) is in the first detection area R1.

[0049] In pattern (5), a reverse signal is input to input port P5. In this case, the sensor unit 5 does not set a detection area, as shown in FIG. 5(A). Pattern (5) is the case when the vehicle body 2 is moving backward and the upper end position of the cargo handling device 3 (the upper end position of the mast) is below the first detection area R1. Note that the sensor unit 5 does not need to store pattern (5), in which a detection area is not set.

[0050] In pattern (6), a first detection signal is input to input port P2, and a reverse signal is input to input port P5. In this case, as shown in Fig. 5(B), the sensor unit 5 sets a first detection area R1, a second detection area R2 (corresponding to the "second area" of the present invention), and a third detection area R3 (corresponding to the "third area" of the present invention) as detection areas. Pattern (6) occurs when the vehicle body 2 is moving backward and the upper end position of the cargo handling device 3 (the position of the upper end of the cargo W) is located in the first detection area R1.

[0051] The second detection area R2 is a rectangular area located directly above the vehicle body 2, with its upper end set at the same position as the upper end of the first detection area R1 (or higher than the upper end of the first detection area R1) and its lower end set at the height of the sensor unit 5. The front end of the second detection area R2 is set at a position that does not detect a rearwardly tilted loading device 3, and the rear end of the second detection area R2 is set at the same position as the rear end of the vehicle body 2 (or forward of the rear end of the vehicle body 2).

[0052] The third detection area R3 is a rectangular area located directly above and behind the vehicle body 2, with its upper end set higher than the upper end of the second detection area R2 (or at the same position as the upper end of the second detection area R2) and its lower end set at the height of the sensor unit 5. The front end of the third detection area R3 is set at a position where it will not detect a rearwardly tilted loading device 3 (in FIG. 5(B) , the same position as the front end of the second detection area R2). The rear end of the third detection area R3 is set behind the rear end of the vehicle body 2.

[0053] In pattern (7), a cargo handling operation signal is input to input port P4, and a reverse signal is input to input port P5. In this case, the sensor unit 5 sets the first detection area R1 as the detection area, as shown in Fig. 3(A). Pattern (7) occurs when a cargo handling operation related to the lifting and lowering operation of the cargo handling device 3 is performed, the vehicle body 2 is reversed, and the upper end position of the cargo handling device 3 (the position of the upper end of the mast) is below the first detection area R1.

[0054] In pattern (8), a first detection signal is input to input port P2, a cargo handling operation signal is input to input port P4, and a reverse signal is input to input port P5. In this case, the sensor unit 5 sets a first detection area R1, a second detection area R2, and a third detection area R3 as detection areas, as shown in Fig. 5(B). Pattern (8) occurs when a cargo handling operation related to the lifting and lowering operation of the cargo handling device 3 is performed, the vehicle body 2 is reversed, and the upper end position of the cargo handling device 3 (the position of the upper end of the cargo W) is located in the first detection area R1.

[0055] When the sensor unit 5 detects an object (upper obstacle C) in the second detection area R2, it outputs a second detection signal from the output port P7. When the second detection signal is input, the vehicle control unit 4A stops the vehicle body 2 or limits the vehicle speed of the vehicle body 2. In this speed limit, the upper speed limit of the vehicle body 2 when moving backward is limited to a first speed (for example, 2 km / h).

[0056] When the sensor unit 5 detects an object (upper obstacle C) in the third detection area R3, it outputs a third detection signal from the output port P8. When the third detection signal is input, the vehicle control unit 4A imposes a vehicle speed limit on the vehicle body 2. In this vehicle speed limit, the upper speed limit of the vehicle body 2 when moving backward is limited to a second speed (for example, 4 km / h) that is higher than the first speed.

[0057] As described above, the forklift 1 sets the first detection area R1 for determining the upper end position of the cargo handling apparatus 3 when the cargo handling apparatus 3 is raised or lowered, and if the upper end position of the cargo handling apparatus 3 is detected in the first detection area R1, sets detection areas (the second detection area R2 and the third detection area R3) for determining the presence or absence of an upper obstacle C when the vehicle body 2 is moving backward. If the upper end position of the cargo handling apparatus 3 is not detected in the first detection area R1, the forklift 1 does not set the second detection area R2 or the third detection area R3. Therefore, the forklift 1 can avoid contact with the upper obstacle C and prevent a decrease in work efficiency.

[0058] Furthermore, the forklift 1 has two detection areas (a second detection area R2 and a third detection area R3) set above the vehicle body 2 and behind the cargo handling device 3. Therefore, the forklift 1 can gradually decelerate when reversing (or stop traveling after limiting the vehicle speed), and can reliably avoid contact with an obstacle C above.

[0059] Note that the forklift 1 in the state shown in Figure 3(A) may detect a shelf in the first detection area R1 when picking up a load. However, when the forklift 1 reverses and moves away from the shelf, it no longer detects the shelf, so the input signal (first detection signal) to input port P2 disappears and the second detection area R2 and the third detection area R3 are no longer set (resulting in the state shown in Figure 5(A)). This allows the forklift 1 to pass under an upper obstacle C that exists in the second detection area R2 and / or the third detection area R3 without stopping or slowing down.

[0060] In the case of the forklift 1, the forklift 1 travels mostly in reverse while carrying a load W. For this reason, in this embodiment, the reverse signal is used to detect an upper obstacle C in the second detection area R2 and the third detection area R3 only when the forklift 1 is traveling in reverse. However, the detection areas can also be set without using the reverse signal (leaving the input port P5 unused). In this case, the pattern of the detection areas for the input signals is as shown in Table 2 below.

[0061] [Table 2]

[0062] Pattern (9) is the same as pattern (1), and pattern (10) is the same as pattern (2).

[0063] In pattern (11), no input signal is input to input ports P2 and P4. In this case, the sensor unit 5 does not set a detection area, as shown in Figures 4(A) and 5(A). Note that the sensor unit 5 does not need to store pattern (11), in which no detection area is set.

[0064] In pattern (12), the first detection signal is input to input port P2. In this case, the sensor unit 5 sets a first detection area R1, a second detection area R2, and a third detection area R3 as detection areas, as shown in FIG. 5(B).

[0065] When the sensor unit 5 detects an upper obstacle C in the third detection area R3, the vehicle control unit 4A limits the speed of the vehicle body 2. When the sensor unit 5 detects an upper obstacle C in the second detection area R2, the vehicle control unit 4A stops the vehicle body 2 or limits the speed of the vehicle body 2.

[0066] When the vehicle body 2 stops traveling, the forklift 1 may enter a deadlock state. As a countermeasure to this, a release button for temporarily releasing the stopped state may be provided on the forklift 1. When the operator operates the release button, the stopped state is temporarily released (for example, for a few minutes), during which the deadlock state can be resolved.

[0067] [Second embodiment] Fig. 6 shows a forklift 1' according to a second embodiment of the present invention. The forklift 1' of the second embodiment has a control unit 4' and a sensor unit 5' instead of the control unit 4 and the sensor unit 5. Except for the above points, the forklift 1' has the same configuration as the forklift 1 of the first embodiment.

[0068] 7 shows a block diagram of the control unit 4′ and the sensor unit 5′. The control unit 4′ and the sensor unit 5′ have the same configuration as in the first embodiment, except that they are provided with a signal line L1′ that connects the output port P6 and the vehicle control unit 4A.

[0069] The vehicle control unit 4A receives a first detection signal from the sensor unit 5' via the signal line L1'. When the first detection signal is received, the vehicle control unit 4A limits the vehicle speed of the vehicle body 2. In this speed limit, the upper limit speed of the vehicle body 2 when moving backward is limited to a third speed (for example, 6 km / h) that is higher than the second speed.

[0070] In the case of the forklift 1 of the first embodiment, for example, if the vehicle body 2 is moving backward at maximum speed when the sensor unit 5 detects the upper obstacle C in the third detection area R3, the vehicle control unit 4A may not be able to decelerate the vehicle body 2 to the second speed (for example, 4 km / h). For this reason, in the case of the forklift 1 of the first embodiment, it is necessary to ensure a certain distance from the rear end of the third detection area R3 to the rear end of the second detection area R2 (enough distance to decelerate from maximum speed to the second speed).

[0071] In contrast, in the forklift 1' of the second embodiment, when the upper end position of the cargo handling device 3 is detected in the first detection area R1, the vehicle speed of the vehicle body 2 is always limited. Therefore, the forklift 1' of the second embodiment can shorten the distance and bring the rear end position of the third detection area R3 closer to the rear end position of the second detection area R2. As a result, the number of times the vehicle speed is limited to the second speed can be reduced.

[0072] Although the embodiment of the cargo handling vehicle according to the present invention has been described above, the present invention is not limited to the above embodiment.

[0073] The loading vehicle of the present invention is a loading vehicle comprising a vehicle body that performs running operations in a specified working area, a loading device that is provided on the front side of the vehicle body and performs lifting and lowering operations, a control unit that controls the running and lifting operations, and a sensor unit that detects objects in a first area, a second area, and a third area above the vehicle body, wherein the sensor unit sets a first area in front of the vehicle body during lifting and lowering operations to detect the upper end of the loading device, and when the upper end is detected in the first area, sets a second area directly above the vehicle body during running operations and sets a third area behind the vehicle body to detect obstacles above the working area, and the control unit can be configured as appropriate so long as it stops the vehicle body from running or restricts its speed when an obstacle above is detected in the second or third area.

[0074] The vehicle speed limit can be set to any speed as long as it is lower than the maximum speed at which the vehicle body can move backward.

[0075] In the above embodiment, the cargo handling vehicle of the present invention has been described using a counterbalance type forklift as an example, but it may also be a reach type forklift or another type of forklift. Furthermore, the cargo handling vehicle of the present invention is not limited to a forklift, and may be a vehicle other than a forklift (for example, a transport vehicle) as long as it is equipped with a cargo handling device that can be raised and lowered. [Explanation of symbols]

[0076] 1,1' forklift 2 Vehicle body 3. Cargo handling equipment 4, 4' control section 4A Vehicle control unit 4B Cargo handling control mechanism 4C Steering control mechanism 4D Driving Control Mechanism 5, 5' Sensor part 5A sensor main circuit 5B Sensor control unit

Claims

1. a vehicle body that travels in a predetermined working area; a cargo handling device provided at the front side of the vehicle body and performing a lifting operation; a control unit that controls the traveling operation and the lifting operation; a sensor unit that detects objects in a first area, a second area, and a third area above the vehicle body; A cargo handling vehicle comprising: The sensor unit During the lifting / lowering operation, the first area is set in front of the vehicle body to detect the upper end of the cargo handling device, When the upper end portion is detected in the first area, during the traveling operation, the second area is set directly above the vehicle body, and the third area is set behind the vehicle body to detect an obstacle above the working area; The control unit When the upper obstacle is detected in the second area or the third area, the vehicle is stopped or its speed is limited. A cargo handling vehicle characterized by:

2. The sensor unit a rear end position of the second area is set to the same position as or forward of a rear end position of the vehicle body; The upper end position of the second area is set to the same position as or above the upper end position of the first area.

2. The cargo handling vehicle according to claim 1.

3. The sensor unit The upper end position of the third area is set higher than the upper end position of the second area, The front end position of the third area is set forward of the rear end position of the second area.

3. The cargo handling vehicle according to claim 2.

4. The control unit outputs a cargo handling operation signal to the sensor unit during the lifting operation, The sensor unit When the cargo handling operation signal is not input and when the upper end portion is detected in the first area, the second area and the third area are set.

2. The cargo handling vehicle according to claim 1.

5. the control unit outputs a reverse signal to the sensor unit when the vehicle body is moving backward; The sensor unit When the reverse signal is input and the upper end is detected in the first area, the second area and the third area are set.

2. The cargo handling vehicle according to claim 1.

6. The sensor unit outputting a first detection signal when detecting the cargo handling device in the first area; outputting a second detection signal when the upper obstacle is detected in the second area; outputting a third detection signal when the upper obstacle is detected in the third area; A signal line is provided to input the output first detection signal to the device.

2. The cargo handling vehicle according to claim 1.

7. The control unit limits the vehicle speed of the vehicle body when the upper end portion is detected in the first area during the traveling operation.

2. The cargo handling vehicle according to claim 1.

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